How to attend university courses for free, online

Coursera is a for-profit educational technology company founded by computer science professors Andrew Ng and Daphne Koller from Stanford University that offers massive open online courses (MOOCs). Coursera works with universities to make some of their courses available online, and offers courses in physics, engineering, humanities, medicine, biology, social sciences, mathematics, business, computer science, and other subjects. As of April 2014, Coursera has 7.1 million users in 641 courses from 108 institutions.

The website and the lectures and the hosted material (videos, assignment, lecture notes) are 100% free but in some cases a fee applies to get (after the final passing of the exam) an official certificate.

The courses are really well done and taught by some famous professors from well-known Universities (e.g. Stanford, Princeton).

MIT OpenCourseWare (MIT OCW) is an initiative of the Massachusetts Institute of Technology (MIT) to put all of the educational materials from its undergraduate- and graduate-level courses online, partly free and openly available to anyone, anywhere. MIT OpenCourseWare is a large-scale, web-based publication of MIT course materials.

Even if the MIT OCW hosts less courses and it is also less organized compared to coursera, is definitely a must!